Machine for cutting screw-threads.



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PATENTED DEG. 3, 1907.

`J. HARTNBSS. y MACHINE PoR 1CUTTING 'SCREW THREADS.

` APPLICATION FILED JUNE 12. 1905.

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J. HARTNBSS.

MACHINE POR'GUTTING SGRBW THREADS;

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/N VEN TUR I Noysvzfzza.. PATENTED DEG. 3,1907

J. HARTMSS.V MACHINE FOR'GUTTmG SCREW THREADS.

' APPLICATION ILED JUNE 12. 1905. l

4 SHEETS-snm 4Q UNITED STATES ArnarnNT OFFICE.

'JAMES HARTNESS, OF SPRINGFIELD, VERMONT.

MACHINE FOR CUTTING SCREW-THREADS.

' Speccaton of Letters Patent.

Patented Dec. 3, 1907.

Application filed J une 12.1905. Serial No. 2641.778.

To all whom it 'may concernz.

Be itknown that I, JAMES HARTNEss, of Springfield, in the county of Windsor and State of Vermont, have invented certain new and useful Improvements in Machines for Cutting Screw-Threads, of which the following is a specification.

This inventionl has relation to metalworking machines and' more particularly to mechanisms or appliances for cutting screw-threads, of which there are at present two classes, to `Wit,-those in which a dieis used comprising a-number of cutters, the cutting edges of which cause their own advancement or lead along the work, and those in which a chasing bar having a single cutter is advanced either by hand, or by 4a toolcarriage in turn actuated by a lead screw. In the latter class of machines are the regular engine lathes in which the carriage is controlled by a long lead screw, usually running i the entire length `of-themachine, and also the chasing attachment for brass working lathes, in which a short lead screw is mount- In such attachments last referred to this lead screw is adapted to be engaged by a ynut-section mounted upon an arm extending upwardly and forwardly from a rod mounted on the bed or the headstock and adapted to slide longitudinally of the bed. This rod also carries an arm upon which is supported a tool-carriage. By swinging the tool-carriage into position, the nut-section is brought against the lead screw. This particular device is generally .used in the formation of threads in a brass lathe butis seldom usedv loutside of that class of work. This attachment is quicker in operation than the engine lathe, but it is not as accurate in'the control of the lead, whereas while the engine-lathe thread-cutting mechanism is moreaccurate, still it is unsatisfactory in many respects for chuck work.- Moreover, since it is necessary.

The present invention has for its obje@ 130 provide an accurate and simple mechanism for feedlng the chasing to'ol by means of l which Imay dispense with the heavy feeding gears necessary to move the chasing tool 1n a carriage.

A further object .is to overcome the frail-- ties which are found in the chasing attachments as used in brass work, and to proyide a mechanism that will be under the most direct control of a lead screw, independent of the feed rod, and which may be set to thread or turn straight or taper work.

According to the embodiment which I have illustrated, the attachment is mounted by a swivel on the top of a ilat turret, and it comprises a frame in which a cutter bar is suitably mounted to slide, said bar being under the direct control ofI a lead-screw, the rotation of which is effected by suitable connections whichinsures its rotation in proper relation to the speed of the Work. It is not essential, however, that the attachment should be mounted upon a turret, as it may be mounted upon any other tool-slide. In order-t0 utilize. this attachment, however, upon a turret-lathe such as illustratedin my VLetters Patent No. 792,591, -grante'd'J-une 20, 1905, in which the headstock is adapted to slide laterally, the rotating shaft is driven bya suitable connection from the spindle,

' and said shaft 4is connected to the headstock by a swiveled head .to accommodate the longitudinal and rotative'movement of the turret and the lateral travel of the head. As will be hereinafter explained, with a single cutter the work may be` threaded or turned externally or internally, and taper work may be turned or threaded with equal facility. y

Referring to the accompanying drawings-Figure 1 represents in plan view a portion of a lathe to which the invention 1s attached. Fig. 2 represents a front elevation of the same. Fig. 3 represents a longitudinal section ofl that part of the attachment which is mounted upon the turret and whichcarries the lead screw. Fig. 4 represents a rear end elevation. of the same.-

Fig. 3. Fig. 11 represents a section on the line 9-9 of Fig. 3 and illustrates the. parts in a position different from that illustrated in Fig. 9. Fig. 12 represents in front elevation the rear end of that portion of the mechanism which is mounted on the turret. Fig. 13 represents in perspective view the rear end of the cutter-bar. p Fig. 14 represents the rear end of the oscillatory controller rod which controls the operation of the cutter andthe nut section. Fig. 15 represents a horizontal section on the line 15-15 .of- Fig. 3., Fig. 16 represents a partial section on the same line and shows the.

cutter as withdrawn .from the work. Fig. 17 (Sheet 2) shows the .cutter-bar and the cutter in section. Figs. 18 and 19 illustrate the cutter or Chaser. Fig.. 20 shows in plan view a portion of the turret `arid illustrates how the angle of lthe frame of the mechanismen the turret may be varied.

Referring to the accompanying draw- \ings,-20 indicates the headstock in which -is suitably journaled the hollow spindle 21 having a chuck 22.

23 indicates a carriage adapted to slide back and forth relatively to the headon ways or shears on the bed, and upon it is mounted the flat turret 24.

As thus far explained, the'lathe may be` substantially similar to thatillustrated in my said Letters Patent No.7 92,591, herein-H before referred to, in whichthe head 2O isy adapted to move laterally to effect acrossfeed of the work.

In Fig. 2, I have shown one of the transverse guides 25 upon-Which the head is mounted to slide. p The attachment, as a whole, includes a removable frame which lmay be mounted upon the turret and which carries the leadscrew, the gearing on the headstock, and a sliding rotary shaft' which connects the said gear mechanism with the operative devices on the turret.

`By examination of Fig. 2, it will be observed that in the cover of the headstock there is an opening 26 which is closed by the circular base of a support or frame '27 secured in place by screws 23. This sup ort is formed with an annular flange 29 in w ch is secured' by a screw 30 an eccentric bushing 31, Swiveled in the bushing is the doyvnwardly extending sleeve 32 of a su ort or head indicated as awhole at 33. T 1s swiveled head forms a bearing for two shafts', the axes of which are transverse to each other.

iA perpendicularshaft 35 is journaled in the sleeve 32 and it carries at its lower end a Level-gear 36 which is adapted to interniesh with and be driven by a bevel-gear 37 upon the spindle 21; The hub of the gear 36 bears against the lower endof the sleeve 32 and the bushing 31, and it is secured to the shaft 35 by a pin 39. It will be seen that the bushing 'other of said bearings.

extends above the ange 29, and that it is rovided with apertures to receive a Spanner,

y .which it may be rotated to Vmove the gear 36 .into-and...out of mesh with the gear 37. The upper end of the shaft 35 has affixed to it a s iral gear 4() by which power is transmtte' to a sliding shaft 41 which extends from the head to the-tooleslide. The head or su port 33 is of the shape shown in Figs. 1 an 2, and has two bearings 42 42 in which the rod or shaft 41 is loosely journaled. Between the bearings there is a. spiral gear 43 which is slidingly keyed tothe rod or shaft 41, and which intermeshes with and is driven by the s iral gear 40 hereinbefore referred to.

'The ead 32 rests upon the upwardly projecting end of the eccentric bushing and being loosely journaled in said bushing may swing or rotate relatively thereto.

The mechanism which is mounted upon the turret or tool-slide comprises a frame 50, the base of which is fitted to rest upon and be removably secured to the top of a flat turret such as is used inniy machines. Any suitable securing mechanismy may be utilized for `this purpose. This frame has an offset upright annular flange 51 in which is loosely journaled a head 57. A In this head is jour naled an upright shaft 52, the lower end of the shaft being journaled in the frame 50, as shown in Fig. 8. Pinned to the upper end of this shaft is a bevel gear 53 which is adapted to be engaged with and driven by a bevel gear. 54 pinned to a sleeve 55 mounted in bearings 56 56 carried by the head 57. The sleeve is held against movement axially relatively to its bearings by the gear 5,4, which abuts against one of said bearings, and a collar 58 pinned thereto which rests against the The end of the rod or shaft 41 is reduced and is assed into the sleeve 55 to which it is secure b a taper pin 59. By removing the in 59, t e head may be reversed and the sha t'introduced into the opposite end of the sleeve which is'a ertured forthe reception of the in 59. his provides for driving the sha t 52 in either direction at will. The swiveling of the head 57 and the head or support 33 provides for maintaining the gears 54 and 53, and the gears 43 and 40, in proper intermeshed relatlon, irrespective ofthe rotative or longitudinal movement of the turret and of the transverse sliding movement of the head- Stock 20.

lll

' The frame 50 is provided with an aperture or guideway for the reception of a longitudinally sliding ,cutter-bar 60. The guideway or aperture may be cylindrical, as may be the cutter-bar, andhence l provide a key 6l. in the frame which extends into a longitudinal slot in` the cutter-carrier to prevent its rotation. In the front end of the cutter-bar or the end which is nearest-the work, is a transverse dovetailed groove 62 for the reception of the cutterorjchaser 63 whichl is thus'adapted to slide transversely of said bar. This bar is located substantially in alinement with theaxis of the spindle, so.

` to another.

that the chaser or cutter may be held in proper relation to the work. It will be apparent that I may em loy a chaser having a number of teeth, as shown, or else a single pointed chaser, if desired;

lnorder that the cutter or chaser may be moved into and out ofvoperative position, the bar 60 has an eccentric aperture 64, in which isy rotativelyV mounted a controllerrod 65 having on its rear end a handle 166 by which it may beturned. 'On its iront end this controller-rod has an eccentric.springepressed pin 66, which' extends into atransverse slot'v 67 in the inner face of the cutter or cli-aser. Consequently, vby rotating the rod 65 in its bearing, the cutter 63 maybe moved into and. out of operative or active position,- the.

pin 66moving from Vone dead'center position A suitable knock-off mechanism is provided f or effecting the automatic rotation of the rod 65.

Immediately above thel tool-carrier 60 there is a feed-rod 68-7 one end 69 of which is' journaled in the frame 50 and the middle pcrtion of which' is jcurnaled in a box .70, secured by a set-screw 71 in the other end of the frame. vThis shaft or feed-rod has the lead screw 72 which is locatedinside of the frame.

prohyided with two adjustable collars 73 74 whlch co'perate with the knock-off mechanism for operating the controller rod 65at any toits active position, the nutsection 75 is forced upwardly into positive and operative engagement with the lead screw 72, as shown in Fig. 10, where it is held by said rod. When, however, the rod is rocked to withdraw the cutter or chaser from thework, the flattened portion o f the cainis moved under the nut section' and the latter is free to dro from e'ngagement with the Ylead screw. fithin the end of the cutter-bar are placed two actuators or ins 77 78 respectively, and they are arrange( in sockets which are transverse to l the carrier, but which converge upwardly, as

shown in Figs. 9, 10, 13 and 14. These two pins rast against shoulders 7 Q Yand 80 formed by recessing the rod 65.A The shoulder 79 1s The rear end ofthe rod 68 projects. .to some distance beyond theV box 70,. and is The in the rear of a vertical longitudinal plane coincident with the axis of said rod and the .shoulder 80 is in front of said plane.

Consequently, by depressing first one pin and then 4the 'th'enthe rod 65 may be rocked in one direction and then in the opposite direction. Qlhe projecting ends of the pins 77 78 are beveled, and are adapted to be alternately engagedvby projections or studs 81 82, located upon the collars 73 74,' respectively. The pm 77 is in advance of the pin 7 87 and when the cutter-bar hasA been advanced'by the lead screw a sufficient distance, the revolving' stud 81 engagesthe beveled end of the pin 77 and rocks the rod to knock off or move the nut section into inactive position and remove the chaser or cutter to its inactive position and away from the work. The cutter-bar is then retracted by a mechanism which will be explained, vuntil .the pin 78 comes into the path of the revolving stud 82, upon .which it will be depressed to again rock the rod 65 1n the opposite direction so as to force the nut section firmly against the lead screw and to move thejchaser or cutter into active or cutting position with relation to the work. The

-lead screw is rotated continuously from the shaft 52 by means of spiral gears 83 84, the former securely pinned to the shaft 52, and the latter being keyed to the feed-rod 68, be-

tween the lead-screw and the 'box 7-0, as

shown in Fig. 8. l

l The upper portion of thecutter bar 60 is concaved slightly to permit of the free rotation of the 'spiral gear 84 and the collars 73 and 74. The rear side of the cutter-bar 60 is formed as a rack or with rack-teeth 85 with which engages a pinion 86 journaled loosely upon'the shaft 52. The hub of the gear 86 'is held frictionally against a friction ring or collar 87 pinned to the shaft 52 by a slidable friction ring or collar 88 and a spring 89, which is interposed between the .last-mentioned ,collar and the hub of the spiral gear 83. The tendency of the friction members under the tension of the spring 89 is to rotate the pinion 8 6 in a directionto retract thev cutterfcarrier except when the nut section is engaged with the lead screw, 1n which event the. carrier will be forced positively towards the work and the pinion 86 will rotate idly in the opposite direction to the disks 87 88.`

I have already stated that the base of the frame 50 may be attached to the turret by any suitable means, but I preferably conthat the Work may be taper-turned, or taper work may be threaded. -That is to say, I form in the base.. an aperture 90 through which a pivoted bolt 91,may be passed upwardly from the flat face' of th`e-turret. A nut 92 on the bolt holds the'base of the frame firmly against the said t'urret. At some little distance in the rear-of the aperture Q() 1s a segmental slot 93 which is the arc of a circle '120 struct the base in the following manner, so i &

the employment of a {special templet or taper-turniiig mechanism. l

Inasmuch as the lathe is provided with the cross-sliding headstock,v the' Work may be moved laterally with -relation to the tool in the tool-carrier, and hence the same cutter,

whether it be a chaser oi a' turning cutter,-

inay'be usedf 3rl threading or turning either the interior or the exterior of the wor In the operation of the machine, the power will be transmitted from the spindle to the shaft 52 through the medium of the sliding rod 41 and the gearing which connects the ysaid rod with the said shafts. :'The manner in which the two heads are swiveled upon their res ective supports or frames prevents any of the parts from binding, and enables the attachment to be used for bar or chucking Work of any size or diameter. While itwi-ll be understood that I prefer to use an interchangeable-lead screw for each pitch of thread to be cut, yet I would not re`- gard it as a departure from my inventionv to include change-gearing in the mechanism which is mounted upon the turret. By the The bolt 93 whose head is aiiixed' In this use of change-gears, the saine chasing apparatus may`be use'd for a few lead'screws or even with a'single lead screw. A few inter- .changeable -lead screws might be preferred, to insure themeshing of the chaserinits work each time.v This would be insured for instance by the employment of a four-pitch lead screw which would cut threads which would be multiples of four. v

According to the present embodiment of the invention, the/cutter bar 6() is projected at its front end from the frame in which it is mounted, but where the attachment is to be used entirely for external work or for internal work having a large diameter, .I would prefer to extend `the sup ort for the said bar beyond the outer end of t e bar when at its extreme limit of movement. The cutter in that event would pass through a slot in the main castinfr.

bHaving, thus explained'the nature of .the invention, and described a Way of constructing and using the same, although without attempting to set forth all of the forms in which it may be made, or all of the modes of its use, I declare that what I claim is 1. An attachment for :i lathe comprising a support or frame adapted to be attached to the tool-slide of the lathe, a lead-screw jour-- nalcd on Asaid support or frame, a cutter arranged to'move on said support or f raine, connections between the cutter and the leadscrew, and power-transmitting connections independent of the slide-moving mechanism of the lathe for transmitting power from the work-.rotating mechanism to the lead-screw.

2. An attachment for a turret-lathe comprising a frame adapted to be attached to the turret, a movable cutter on the frame, a' lead-screw and nut on the frame for moving the cutter independently of the movement of the turret, and swivel connections for driving the lead-screw from the work-rotating mechanism adaptedI to be connected to the headstock and turret respectively.

3. In a turret lathe, a bed, a head-stock having work-rotating mechanism, a carriage, a turret, and a cutting attachment comprising a frame on the turret, a cutter, a nuta'nd a lead-screw mountedon the frame for feeding the cutter, a power-transmitting shaft extending from the head-stock longitudinally of the bed towards the frame and powertransmitting connections connecting said shaft respectively with the work-rotating mechanism in the head-stock and with the said lead-screw.

4. An` attachment for a lathe comprising a frame adapted to be attached to the toolslide, a cutter-bar movable in said frame, a lead-screw journaled on said frame and movable with the tool-slide, means independent of theslide-moving mechanism for rotating said lead-screw to feed the cutter'- bar, and means onsaid frame independent of the lead-screw forretracting the cutter-bar 'when the nut is disengaged from the leadscrew.'

5. AnA attachment for a lathe com rising a sup ort adapted for attachment to t 1e headstoc asupport adapted for attachment to the tool-slide, swiveled heads on said supports, ashaft journaled in said heads and slidable with relation .to one of them, means on the first-mentioned support by which power is transmitted to said shaft, a cutter on the second-mentioned support, and means on said second-mentioned support for transmitting power from said shaft to said cutter.

6. An attachment for a lathe com rising a suppiort adapted for attachment to t e headstoc a supporty adapted for attachment to the tool-slide, a shaft jouriniled on said supports and sldable with reference to om` of them, means on the first-mentioned support for transmitting ower to said shaft, a cutterl onthe secon .-inentioned support, and means on saidsecoiid-inentioned support for transmitting power from said shaft to vsaid cutter.

7. The combination lof a frame adapted for attachment to the tool-slide of a lathe, a cutter-bar thereon, alead-screw journaled -in said frame, ,a nut connected to the cutter bar, a cutter arranged transversely on said movable bar and movable relatively thereto, and

means for moving said cutter and nut relaattachment to the tool-slide of' a lathe, a' thereon, yieldingly cutter bar driven gearing tending constantly to retract the cutter-bar, a positively driven leadscreW on said frame, and a nut connected to lthe cutter-bar and adapted to be 'engaged with the lead-screw to feed the cutter-bar relativelyto ,the frame and the lead-screw.

10. The combination of a frame adaptedl for attachment to a lathe, a movable cutterbar -thereon, a nut connected to the cutterbar, a lead-screw journaled on the frame and adaptedV to positively feed the cutter-bar, a rack on the cutter-bar, and a yieldinglv driven pinion intermeshing with said rack to vretract the cutter-barv when the nut and lead-screw are disengaged.

11. The combination of a frame adapted for attachment to a lathe, a cutter-bar mounted to slidelthereon, a lead-screw on the frame, a nut connected to the cutter-bar and movable into and out of engagement with the lead-screw, yieldingly driven gearing tending constantly to Withdraw the cutterbar, and automatic mechanism operable to throw the nut into and out of engagement with the lead-screw.

12. An attachment for turret lathes comprising the combination with a power-transmitting sh'aft,` of a Jframe having a leadscreviT thereon, ahead on the frame, a shaft j ournaled on said head, means comprising an upright shaft geared to said power-transmitting shaft for connecting said shaft tothe lead-screw, and means for swiveling said head on the frame.

13. An attachment for lathes comprising the combinationwith a power-transmitting.

shaft, of a frame having a lead-screw thereand intermeshing with said last-mentioned on the head to said power-transmitting shaft.. f

14. The combination with a cutter-bar on, an upright shaft geared to the lead-screw and having a gear on its upper end, a head sWiveled on the frame about the 'axis of the upright shaft, a gear jouinaled on the head gear, and pro visions for-connecting said gear having a rack, a lead-screw, anut connected tothe cutter-bar, means-by which the nut may be engaged with the lead-screw, a shaft, i

gearing connecting the lead-screw and the shaft, and a yielding pinion on the shaft intermesliing with the rack, said lead-screw and said pinion being rotated to respectively advance and retract the cutter-bar.

15. In a mechanism of the character described, the combination of La frame, a cut-4 ter-bar arranged to slide longitudinally on` said frame and having a transverse guide- Way, a cutter arranged to slide 1n said guide- Way transversely of said cutter-bar, and

automatic mechanism comprising a mem-- ber'for moving said cutter and stops alternately coperating with said member, for

alternately advancing and retracting said cutter to and from active position.

16. n a mechanism of the character described, a combination of a frame, a cutter- -bar arranged to slide in said frame' and having atransverse guideWay-in its end, a cuti. ter mounted to slide in said guideway, and a member within said cutter-bar for moving said cutter relatively to said cutter-bar, and a nut and a lead-screw parallel to said cutterbar for moving said cutter-bar relatively to said frame. l

1:7. In aV mechanism of the character described, thecombination of a frame, acutter-bar onsaid frame, a nutand a lead-screw i for moving `saidicutter-bar on said frame, a cutter arranged to slide transversely of said cutter-bar, and a controller rod located Within said cutter-bar and having an eccentric pin on its end for actuating said cutter.

18. An attachment for a lathe comprising a frame ada ted to be secured to the toolslide of the atlie, a cutter mounted to slide on said frame, lead-screw mechanism on said frame for actuating said cutter, removable gearing adapted to be secured to the headstock of the lathe for operative engagement with the Work-rotating mechanism, and extensible means connecting said gearing with the said lead-screw mechanism on the frame.

19. An attachment for a lathe comprising a frame adapted to be secured to the toolslide,I a cutter-bar on said frame, a leadscrew journaled on said trame, a nut-section located in a socket inthe cutter-bar and ada ted to connect said cutter-bar With said lea -screW, a rocking-controller rod Within said cutter-bar for actuating said nut-section, and means for` automatically rocking said controller rod.

In testimony whereof I have affixed my signature, in presence of tWo Witnesses.

' JAMES HARTNESS.

Witnesses:

MARTIN J. MEARA, 

